SAN JOSE, California (AP), Jul 05 _ A consumer advocacy group has expressed outrage over Apple Inc.'s battery replacement program for the iPhone, while developers and hackers are trying to figure out ways they could expand the capabilities of the hot new gadget.

The hybrid cell phone, iPod media player and wireless Web-browsing device launched to much fanfare on June 29. On the same day, the Foundation for Consumer and Taxpayer Rights fired off a letter to Apple and AT&T Inc., the cell phone's exclusive carrier, complaining that customers were being left in the dark about the procedure and cost of replacing the gadget's battery.

The iPhone's battery is apparently soldered on inside the device and cannot be swapped out by the owner like most other cell phones.

Apple spokeswoman Jennifer Hakes said Thursday the company posted the battery replacement details on its Web site last Friday after the product went on sale.

Users would have to submit their iPhone to Apple for battery service. The service will cost users $79 (euro58), plus $6.95 (euro5.10) for shipping, and will take three business days.

The procedure is similar to the one it has for the company's best-selling iPod players, but because some users will not want to live without their cell phones, Apple is also offering a loaner iPhone for $29 (euro21) while the gadget is under repair.

Harvey Rosenfield, founder of the Santa Monica, California-based consumer watchdog group that wrote the letter last week, contends the iPhone's battery and repair costs should have been clearly disclosed earlier. The company outlined its cellular service rates and many other features of the iPhone in advance of its launch, which drew snaking lines around stores across the country.

``Some of them might be waking up now,'' Rosenfield said, ``wondering who they got in bed with.''

Apple did not have an immediate comment on the consumer group's concerns.

Rosenfield said he did not detect the battery information, which is located under several layers of links on Apple's support page on its Web site, until earlier this week. Technology blogs also started reporting their discoveries of it this week while one of the questions Wall Street Journal tech columnist Walt Mossberg fielded Thursday from his readers was about what happens when the iPhone battery dies.

``The cell phone industry is notorious for not being consumer-friendly while Apple has a fairly good reputation, so for Apple to stand on a technicality of a hidden disclosure that's going to cost the user as much as 20 percent of the purchase price I think will prove to be a colossal mistake,'' Rosenfield said.

The iPhone costs $499 (euro366) or $599 (euro439), depending on the model, and requires a minimum two-year $60 (euro44)-a-month service plan with AT&T.

The consumer and taxpayer organization has gone to court over these kinds of issues in the past. It is embroiled in a pending lawsuit against Cingular, now part of AT&T, over its service termination fees, and is also one of the plaintiffs in a pending lawsuit against Apple over an early model iPod Nano that was allegedly defective because it scratched easily.

In addition, Rosenfield said, replacing the iPhone battery should be free to begin with while the product is under its one-year warranty.

He also questioned why Apple chose to go against the norm of what cell phone users are accustomed to _ swapping out their own batteries and generally at a cost that is less than half of what Apple is charging now for the iPhone.

``I'm just surprised at Apple's decision to defy the common practice of allowing people to purchase replacement batteries,'' he said. ``And the fact that the information is buried is just not appropriate.''

Apple has not disclosed how many iPhones were available at launch, though analysts have speculated the amount was 500,000 or more. AT&T said the gadget had sold out at most of its stores on the night of the launch while many Apple stores ran out of stock by early this week. Those ordering the iPhone online through Apple's Web site on Thursday were being promised delivery would be in two to four weeks.

Meanwhile, software developers anxious to find ways they could introduce applications tailored for the iPhone's Web browser were preparing to get together in Silicon Valley this weekend at an ad hoc conference called iPhoneDevCamp.

Also, a tech-savvy audience cheered the latest work this week of a hacker known for cracking copy-protection technology and creating workarounds of Apple products. Jon Lech Johansen, also known as ``DVD Jon,'' posted on his blog Tuesday a method for people to turn on the iPod and Wi-Fi features _ but not the cell phone functions _ of the iPhone without going through the required activation process and service fees of AT&T.